The present invention relates to an automatic adjusting device for a disc brake.
A like adjusting device is known from German printed and published patent application 21 43 575 and its counterpart U.S. Pat. No. 3,783,981 issued Jan. 8, 1974 to J. Burgdorf. In this known adjusting device, the adjusting nut is of an outwardly stepped design. Arranged on the step is an axial bearing which is urged by a helical spring against the nut; the other end of the helical spring bears against a sleeve-shaped stop that is formed fast with the housing. At its end remote from the brake piston, the adjusting nut abuts on a second axial bearing which takes support on the bottom of the cylinder bore. In this arrangement, a hand brake clearance remains between a cone surface disposed at the adjusting nut and a hand brake piston which is part of the mechanical actuating device.
Admittedly, this known adjusting device operates generally satisfactorily. It entails, however, a quite complicated design inasmuch as two axial bearings are required. Moreover, due to the arrangement of these two bearings, the space available radially is confined so that the friction clutch can only have a relatively small diameter which may impair the reliability of force transmission.